ESAB Caddy Tig 1500i TA34, Service Manual

Page: 47 / 50

SERVICE INSTRUCTIONS
0740 800 186 - 47 - © ESAB AB 2016
7. Switch off the machine. Disconnect the voltage test cable and reconnect connector
20XS4 to terminal PS of circuit board 2AP1.
8. Disconnect connector 15XS3 (supply to the fan) from terminal E of circuit board 2AP1.
Connect the 24 V DC input of the SST 3 to terminal E of circuit board 2AP1.
9. Connect the 24 V DC output of the SST 3 to terminals N1 and N2 of power board 15AP1.
Circuit connections and measuring points for soft starting
10. Switch on the power source and set it to MMA mode.
11. Check that the DC voltage across smoothing capacitor 15C1 is 22-24 V.
12. Check that the DC voltage at the welding terminals is about 6-7 V.
13. If all the measurements are as described above, reconnect the wires to restore the
power source to normal operation mode and make a test weld.
The PFC circuits are not active in soft starting mode. To check that the PFC is working
properly, measure the intermediate voltage when the power source is in normal operating
mode. See: Power factor corrector in chapter "Description of Operation".
Mounting components on the heat sink
Thermal paste
Apply thermal conducting paste to the components before fitting them to the heat sink.
Start by cleaning the heat sink, and then apply a very thin , even layer of thermal paste to the
contact surfaces of the components. The purpose of the paste is to fill out any hollows in the
surfaces of the components and the heat sink. Those parts of the component and the heat
sink that are in true metallic contact may already have good thermal contact.
Mount the components as described below.
See the spare parts list for the order number for thermal paste, roller and roller handle. Use
only the paste recommended by us.
Fitting instructions
15AP1 Power board with semiconductor module
1. Clean the heat sink and apply thermal conducting paste to the semiconductor module as
described above
2. Fit the board and tighten the screws to a torque of 2.5 Nm, and then further tighten them
to 4.5 Nm.
3. Tighten the screws that connect transformer 15TM1 and capacitor 15C1 to circuit board
15AP1 to a torque of 4.5 Nm